The present invention is directed to a table-shaped jig for positioning elements on a support according to a reference layout. The invention is directed specifically to a table jig which enables the accurate arrangement of embossing plates on a chase, which is destined to be, thereafter, inserted into a machine designed for converting or embossing material, such as sheets or webs.
Embossing is an operation which has an engraved embossing plate with a configuration pressed either cold or hot against paper or a board mash to cause a relieved ornamentation impression. Effected also with the virgin paper, however, this operation is more often usually used in the practical sense, in many cases in which an additional application of a foil is provided on a preprinted paper with color motifs or designs with an enhancing and, thus, highlighting certain printed areas. This involves, however, a high precision positioning of the plates on their case or support with a tolerance of no more than a quarter of a millimeter, which tolerance depends on the prints on the paper or the printable film.
In order to achieve this operation, the operator uses the printing plate layout available in the form of a transparent film showing the corresponding areas of the various plates arranged in alignment with appropriate marks in the flat position on the chase. The images are, thus, fixed on only one side.
At that stage, the operator is then able to place them embossing plates successively on the film in order to shift them individually to a point of the chase corresponding to the printed image on the film. When viewing through the film, the operator is then able to, more or less, adjust the position of the plates before securing them on the chase. However, the observer can realize that the accuracy of such a position depends on the accuracy of the film position with regard to the chase, which can no longer be reliably accurate on account of the fact that the film has to be raised in order to allow the insertion of the plates between the film and the surface of the chase. Moreover, the initial film is likely to become damaged when being frequently manipulated during successive arrangement of the embossing plates on the chase.
The operation would even become more hazardous if only one opaque printed sheet should be available. In fact, for the reasons of coincidence with the direction of the printing process, the sheet is to be arranged on the chase with its printed side turned against the latter. Previously, the operator is to cut out, from the sheet in the area of every print to be embossed, one or several windows, generally of a triangular shape and of which one of the apexes will be directed towards a characteristic part of the motif or design. Proper positioning of the embossing plates inserted between the sheet and the chase can, thus, only be achieved by viewing across these windows, which is often times awkward.
The operator would then mount the equipped chase into the machine and carry out some test prints in order to determine if corrections in the position of the plates must be made. Depending on the complication of the motif or the design, several test prints and correlations might be necessary. This shows how the preparation of the chase or the embossing support is likely to consume a certain time of, say, four hours, during which the machine is not operational. Moreover, this operation would ultimately lead to marginal precision, only with regard to the arrangement of the embossing plate.